Friction shock absorbing mechanism



p 13, 1932- G. 'A. JOHNSON 1,877,329

' FRIQTION S HdCK ABYSORBING' MECHANISM Fil'ed Apiil 16. 1930 2 Sheets-Sheet 1 InvenZZr 'eofgeflrfolnaan G. A. JOHNSON 1,877,329 FRIGTIOB SHOCK ABSORBING MECHANISM Filed April 16,. 1930 2 Sheets-Sheet 2 i I 2/ Z6 i uNrrEo STATES PATENr GEORGE A. .romvso wor cnrcneo, ILLmoIs, ASSIGNOR ro w. H. MINER, me

I is

Patented Sept. 13, 1932 Fries CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE I V FRICTION SHOCK ABsoR rNq MECHANISM,

Application filed April 16,

This invention relates to improvements in friction shock absorbmg .mechanlsms especially adapted forrailway draft riggings. One object of the invention is toprovide a provide in africtionfshock'absorbing'mechanism of the character indicated'includin'g a, relatively movable friction: shell and spring friction shock' absorbing mechanism affording free spring action during the first part of the compression-stroke followedby high combined frictional and spring resistance produced by means including a friction shell and spring cage, which are relatively movable with respect to each other to an extent less than the full compression stroke of the mechanism, and springresistance means opposing saidrelative movement to provide for the free spring action, and wherein the high frictional resistance is produced by a plurality of friction shoes cooperating with the friction shell and wedge means for creating pressure between the shoes and shell, the shell 1 having longitudinally disposed interior friction surfaces arranged about the axis thereof with which the shoes engage, the cooperating surfaces of the shell and shoes being so designed as to guide the shoes lengthwise of the mechanism and hold'thesame against circumferential displacement with respect to the shell. 7 e Another object of the invention is to provide a friction shock absorbing mechanism as i so specified in the preceding paragraph, whereinthe wedge has wedglng engagement with the shoes along faces so arranged as to provide an ecpualized,radially, outwardly directed 'wedging action and the shell is of hexagonal interior cross section, presenting a pluralityof flat, interior friction surfaces converging inwardly of the shell, and the co operating shoes are three in number, each shoe having a V-shaped friction surface cooperating with two adjacent 'shell surfaces, whereby uniform distribution of the stresses in the shell is had with resultant maximum capacity and strength to resist bursting strains for a shell of given size and thickness is obtained, andwherein a spring follower is interposed between the spring resistance and the friction shell and has an enlargement cooperating with the shoes on which the inner ends of the shoes bear, the enlargement being designed to present abutment 1930. Serial no. 44 ,674.

surface areas giving bearing support'for the inner ends ofthe V-shaped shoes inall operative positions; thereof.

Yet anotherobject of the invention is to cage, a spring follower. within thecage, the shell and cage being provided with interengaging flanges limiting outward movement forminga shell of interior, polygonal cross section and providingthe spring follower with a polygonal enlargement or flange section engaging and fitting within the. inner end of the shell; -l

A still further object of the invention is to provide a mechanism of the character indicated in the preceding paragraph wherein the retaining flange portion of theshellis assembled with the cooperating retaining shoulders of the cage by lateral displacement of the shell and cage relatively toward each other, and wherein the parts are at all times, in all operative positions thereof, held interlocked through the medium of the spring follower, after being assembledyby telescoping of the flange vofjthe spring follower within the inner end of the shell;

Other objects of the invention will more clearly appear from the description". and claims hereinafter 'following- In the drawings, forming a part of specification, Figure 1' isa horizontal; lon-' gitudinal, sectional viewthrough the underframe structure of a railway car, illustrating my improvements therewithQthe section through the friction shell member being on two-planesat an angle to each other. Figure 2 is'a front, elevational view of the shock absorbing mechanism proper" illustrated in Figure 1. Figures 3'an d 4 are transverse,

sectional views correspondingrespectively to the lines 3-3 and 44 of Figurel. 'Figure 5 is a side elevational view of; the front end portion of the springcage and the frictlon shell of my improvedshock absorbing mechanism, And Figure 6 is a longitudinal, vertical, sectional view of the front end por the side walls, the top and bottom sides of tion of the spring cage, together with the friction shell, corresponding substantially to the line 6-6 of Figure 2.

In said drawings, 1010 indicatesspaced channel-shaped center sills of the railway car ugiderframe, to the inner sidesjofwhich are secured the usual front stop lugs 1 1-11 "and rear stop lugs 1212. Theinner end part of the-coupler shank of the railway car is designated by l3 andahoo ded yoke 14; is operatively connected thereto. My improved shock absorbing mechanismand'a front'main follower 15 are disposed within the yoke,

and the yoke in turn is supported'by the usual: detachable saddle plate. 16 secured .to the'bottom flanges of the draft sills 10.

In carrying out my-inventiom l provide broadlyv a spring cage casting A;,a1friction shell member B ;1a-spring follower. G ;V a plurality offriction shoes D-D and E; a wedge .blockF; a main spring resistanceGr and a retainerbolt o r The spring cage casting A is of substantially' rectangular" boxrlike form having paced, longitudinally extending. Vertical side walls .17.17, horizontally disposed spaced topandbottom-walls 18,-18 and a verticalrearend wall 19. The end wall 19 cooperates with the stop lugs 12 inthemanner of the. usual rear follower. I As most clearly-illustrated inFigure6, the sidewalls l717 of the casting A extend an appreciable distance forwardly of. the front end portions of the top and bottom walls 18-18,

" the frontend portions of the latter,"which are indicated by 20-120, serving as. transverse abutment shoulders fora PUTPOSQfllGI'G- inafter pointed out. Forwardly of the iabutment shoulders 20' f20, the side walls 17-'17 are provided; with inturned sections 21-21 presenting vertically disposed retaining shoulders 2222 spaced forwardlyv from the abutment shoulders 2020, hereinbefore re- 1 ferred to. i Outwardly' beyond the inturned sections 21 21, the side walls have extensions 23.-'23 whichlembrace thei sides of the friction shell' member-B andrform guide means for the same As most. clearly illuscutv away at the .top and bottom' sides along curved lines, thereby presenting a forwardly projecting wing or. arnrof the formation shown in Figure 5. Eachlside wall17 is also provided with-an interior, longitudinally exure 1: The guide ribs Zak-524i of the-twowalls 1 ?v are in transverse alinement and cooperate with the spring follower'Cfina manner hereinafter pointed out to guide the same in its movement inwardly of the spring cagei As will .be evident, the top; and; bottom; walls 1818 of the spring cage being shorter than the cage at the forward end are provided with transverse openings to permit entrance vof the flanges of the spring follower and fricclearly shown in Figures 2, 3 and 4, the top andbottom wall sections of the shell are disposed horizontally and the sections-forming.

theside walls comprise top sections whichare inclined downwardly andoutwarly, and'bottom sections which are inclined downwardly and inwardly. The wall sections-of the hexagonal shell present six,longitudina;lly disposed:

.fiat interior friction surfaces 25 25, which are arranged symmetrically about the longitudinal axis of the mechanism and converge slightly inwardly.

At theintersection. of'

each adjacent pair of friction surfaces'25 25,

ures 2, .3 and 4, asindicated at 26. 'Each curved surface section 26 is of uniformly the interior surface of the friction shell is; curved, or rounded, as, clearly, shown n Fig;

varying radius from the outer end of the: j

shell inwardly, being of. greatest radius; at p the forward end and of smallest radius atthe rear end of the shell, as clearly shown inFigr' ures 4 and-3 respectively, As will be'evident,

each pair of adjacent friction surfaces 25-25,

together form all-shaped friction surface sectionwith which afriction shoe cooperates, as hereinafter clearly pointed. out At: the.

inner end, the shell .13 is. provided with a pair of laterally projecting flange members 2'. 2Z which are located between. the abutment shoulders 20 and the retaining shoulders 21 of the spring cage and are adapted to engage the retainingishoulders-to limit the outward movement of the shell.. Midway between the top and bottom portions, the flange members 27 27, are notched orcut away, as indicated at 28.28 tov cooperate withthe guide ribs 24 -24 of the spring cage. I}. The top and bottom'wall members of the shell are reinforced by'relatively shallow, longitudinally extending ribs 2929, which are adapted to cooperate, with the top and bottom arms of the yoke member 14. The opposite sides of the shell B arealsoreinforcedbyex? 1 wide rib members 30-30, which are embraced by the guides 23'-23 of the spring cage and are guided therebetween to preventrocking or tiltingof the friction shell.

'terior, longitudinally extending, relatively The friction shoes, which are three in numher. and are indicated by D-D andE, are arranged symmetrically about the axis of the mechanism, each shoe having a VV-shaped outer friction surface31 cooperating with a pair of adjacent friction surfaces 2525 of the friction shell. The friction shoes D-D and E are all of like design, except as hereinafter pointed out. On the inner side each shoe is provided with an enlargement 32 having a wedge face 33 cooperating with the wedge block F. The wedge faces of the shoes D D are disposed at relatively blunt angles with respect'to thelongitudinal axis of the mechanism, while the wedge face of the shoe E is disposed at a relatively keen angle with respect to said axis. The V-shaped friction surface 31 of each shoe has the two angularly disposed sections thereof arranged to fit and properly engage the cooperating friction surfaces 25 of the shell. The two sections of the friction surface of each shoe are connected by a curved portion 131 at their intersection, which is uniform from front to rear of the shoe and corresponds to the-curvature of greatest radius of the curved surface 26, which connects thecorresponding friction surface 2525. f The wedge block F bears at its forward end on the inner side of the main follower 15, the latter cooperating with the front stop lugs 11 in the usual manner. At the inner end, the wedge block F has three wedge faces up 34-34 and 35 arranged symmetrically about the axis of said block-,the wedge faces 3434: being disposed at relatively blunt angles .while the wedge face 35 is disposed at a relatively keen angle. The wedge faces 34-34c cooperate with the wedge faces 3333 of the shoes D, while the wedge face 35 cooperates with the keen wedge face 33 of the shoe E. I The spring follower C, which is interposed between the inner end of the friction shell B and the main spring resistance G, comprises a main body portion 36 which is in the form of a substantially rectangular plate-like membeiyand is provided with a central opening 38 for a purpose hereinafter pointed out. The plate section ofthe spring follower C normally bears directly on the inner end of the frictionshell. At the forward side, the spring follower is provided with a projecting flange member 39, which surrounds the opening 38 and is of substantially hexagonal outline so as to interfit with the interior of the friction shell B. As most clearly shown in Figures 1 and 6, the flange 39 protrudes to a considerable extent and extends into the friction shell such a distance as to engage the inner ends of the friction shoes D-T) and E. The amount of projection of the flange portion 39 ,is preferably such as to exceed the amount of relative movement of the friction shoes and shell B, so that the hexagonal flange member will at no time during the operation of the friction shock absorbing mechanism be disengaged from said shell. As will be evident due to the hexagonal formation of the projection or flange 39 of the spring follower and the corresponding interior section of the friction shell, these two parts interfit and lock together so as to prevent relative rotation of the same. The op posite vertical sides of the plate section 36 ,of the a spring follower C are centrally notched or recessed, as indicated at l-O0, to cooperate with the guide ribs 24*24 of the spring cage. The height of the spring follow-er G is such that the same will fit between the top and bottom walls 18-18of' the spring cage and move freely inwardly of the cage. The main spring'resistance G comprises a pair of central spring members 41 and 4.2 and four additional coil spring members 43-43 spaced about saidcentral members.

The central member il is: disposed within the member 42 and comprises a relatively light coil having its inner end bearing on an lnwardly extending hollow boss 46 formed on the end wall 19 of thespring cage. The

forward end of the coil 41 extends freely through the openings 38 of the spring follower and engages a spring follower disc 44 hearing 011 the enlargements 32 of the friction shoes. The spring 42, which surrounds the spring 41, is of relatively heavy con. struction and has the forward end thereof bearing on the spring follower C. The rear end portion of the spring 42 surroundsthe boss 46 and bears directly onthe end wall 19 of the spring cage. The four outer coils i-343 of the spring resistance Gare dis posed in the four corners ofthe spring cage mo and have their opposite ends bearing respectively on the spring follower C and the end wall 19 of the spring cage. i

The mechanism is held assembled and of uniform over-all length by .the retainer bolt 195 H, which has its oppositeends anchored respectively to the wedge block F and the hollow boss 46 of the rear end wall 19 of the spring cage, the head of the bolt being. dis posed within said hollow boss and the shank thereof extending through the inner coil 41 of the spring resistance, alined openings in the hollow boss,spring follower disc 4A; and wedge block F. The nut of the retainer bolt is disposed within a pocket or recess 45 pro vided in the wedge block F. 7 I

When-the mechanism is assembled, the retainer bolt 'holdsthe spring resistance, including the coil 41, under a certain amount of initial compression. As will be evident, the spring 41 extending through the spring follower C and directly cooperating with the friction shoes compensates for wear of the various friction and wedge faces of the mechanism, inasmuch as the tendency of this. spring to expand maintains the shoes pro-f jected outwardly, while the retainer bolt limits the outward movement of the wedge block;

In assembling the parts of my improved 13 shock absorbing mechanism, the four outer COllSOf the spring resistance G are first. in-

Vserted within the spring cage and placed in position in the corners thereof, the heavier coil 42 being then inserted therebetween.

inwardly and the springs l2 and &3 compressed, until the forward end portion of the projection or flange 39 of the spring follower clearsthe retaining shoulders 22 22 to such an extent as to permit insertion ofthe retaining flange portions 2'Z.'2Z of tie friction'shell' between the forward side of the plate-like portion ofthe spring follower and said shoulders; The friction shell is then assembled with th'espring cage by passing the flangemeinbers 27 27 thereof into the open ing between the shoulders 20 and 22, engag ing the flanges 2'? in back of said shoulders 22. Vl Vhentheshell has been brought into substantial axial alinement with the spring cage, the 39 of the spring follower will be alined withthe interior of the shell so that the. parts will be telescoped when the pressureon the spring follower is relieved. As villbe evident, upon outward movement of the spring follower the same engages within the inner end of the friction shell and prevents vertical lateral displacement of the same with respect to the spring cage, there.-

by. holding-the same positively assembled therewith. I

Two very important considerations in friction gearsare the prevention of circuinfer ential shift of the shoes and the maintenance of'full area contact between the friction faces under all conditions of operation. VVithmy improved construction, due to the angular arrangement of the fiat friction faces of the shell and each slioe,.respectively, a'combined friction surface is formed, whichabsolutely prevents circumferential shift of the shoes. In this connection, it will be noted also that the three shoe arrangement in corn j unction'w'ith the three-faced wedge, insures equalized radially outwardly directed forces on the three shoes and also that each shoe, 111 effect, has a wedging action against the friction shell. lhis last mentioned wedging action of the shoes laterally against the shell further serves to positively insure uniform stresses in the shell, since it will be apparent that each diametricallyopposite and parallel set of sections. ofthe shell will be pressed After the main portion of the follows full area contact between the friction surfaces of theshoes and shell, it willgbe ob.- served that this is=maintained on the con verged friction surfaces in anyposition of the shoes with respect to the shell. Due to 70 the fact that initially there isonlyline con 'bility of the shoes being lifted off from the n at friction'surfaces of the shell, and hence there will always be full area cont-act be tween-the two pairs of flat friction faces of the shoes and shellrespectively. During the inward movement of' tlie shoes anddu'e to the slight spacing initially occurring at the curved faces above mentioned, it is evident th'atthere will be an equally distributed-pressure radially outwardly againstboth flat'sections of each shoe and this will remain true, notwithstanding the tapered or converged formation of the friction shellsurfaces;

It is further pointed out that'due totheil) formation of the curved surfacesof theshoes and shell, as the shoes are moved' 'inwardly of the'tapered-shell, there; no 'danger' of the edges of the shoes gouginginto orabrad' ing the shell surface at the corners, which-if not prevented, might start a line of scoring which would so Weaken the she'll'that the cuts ward pressures wouldsoon fracture or disrupt the shell; In other words, while the edges of each pairof adjacent shoes approach 460 each other during a compression stroke due to the taper of the shell, the'curve'di' surfaces at the corners between the edges of the shoes prevent undesirable 'imb'edding, or scoring above inentioned,while permitting the maximum area. of contact between the shoe and shell faces. Further, because of the curved faces opposite; the angles ofthe friction shoes, should there be any variations between the angularity of'the flatfaces of the shoes and shell, the, opposed curved formationsro-f the shell and shoes facilitatethe relatively rapid 1 seating of the shoes onxthe shell without dan ger ofundesirable scoring or abrasionat the corners of the shellopposite the ciorners of V the shoes, andafter the mechanism 'has be'enr compressed a few times, a perfect seating will be obtained, and in fact, a somewhat en"- larged area of contactproduced" due to the merging of the curved faces into the flat faces of both the shell and shoes. V The operation of. my improved friction shocl: absorbing mechanism, during a compression stroke, either in buff or draft-,is'as The main follower 15* and the spring cage A will be jmoved inwardly toward each other, therebyforcing'the wedge r block F inwardly also. Due to the inward movement of the wedgeiblock' F, the friction a, shoes D-D and Ewill be wedged apart and its mage I stop shoulders -20 formed by the front end portions of the top and bottom walls 18-18 of the spring cage. When the friction shell is thus arrested, the friction shoes will be compelled to move inwardly of the shell during the remainder of the compression stroke. Inasmuch as the shoes directly engage the flange 39 of the spring follower C, the latter will be forced rearwardly in unison with the shoes, thus further compressing the coils 42 and 43-43 of the spring resistance, while the coil 41 is also compressed through direct engagement with said shoes. Inward movement of the friction system within the shell 13 is finally limited by engagement of the main follower 15 with the front end of the shell, the actuating force being thereafter transmitted through the shell and spring cage A, which form solid column means for this purpose.

During release, when the actuating force is removed, or reduced, the expansive action of the main spring resistance G will force the friction shoes and spring follower C outwardly, carrying the shell B therewith. Outward movement of the shell is finally limited by engagement of the flanges FIT-27 thereof with the retaining shoulders 2222 of the cage. After movement of the shell has been arrested in release of the mechanism, the shoes will be forced outwardly by the five coil springs of the spring resistance, which act directly on the spring follower C and by the central coil 41 of the spring resistance,

which directly engages with the shoes. Outward movement of the spring follower is pos? itively limited by engagement with the inner end of the friction shell, while movement outwardly of the shoes is limited through the retainer bolt, which limits outward movement of the wedge block.

From the receding description taken in connection with the drawings, it will be evi dent that by providing the spring follower having the flange of hexagonal formation, which telescopes within the inner end of the friction shell, these two parts are locked against relative rotary displacement and inasmuch as the flange of the follower extends into the shell, in the normal position of the parts, to an extent greater than the relative movement between the friction shoes and the shell, there is no danger of the spring follow er at any time becoming disengaged from the.

' the claims interior the shell, thereby, avoiding the danger, of the shell becoming displaced laterally withrespect to the spring cage during thez operation of ,the mechanism, especially plate portion is spaced inwardly from the during. release, when the spring follower in -ner endof the friction shell. Displacement or the-shell with respect to the spring cage further prevented by theforwardly pro- Y jecting guide arms 2323 of, the cage and by tle r b and. groove connection provided be tween the flanges of the friction shell and the 1240f the springcage and the plate-like portion of the spring follower and said ribs. I have hereinshown and described what I now consider the preferred manner of carry ing out my invention, but the same is merely llustrativeand I contemplate all changes and modifications that come within the scope of appended hereto. "Iclaim: g

1; In a' friction shock absorbing mechanism,;the combination with a spring cage having a set of top and bottom opposed walls and a set of spaced side walls, one of said sets of opposed walls having outer retaining shoulders, and the other set of said walls having end abutment shoulders spaced inwardly from said retaining shoulders; of a hexagonal friction shell having lateral flangesengaged in back of said retaining shoulders, said shell being movable lengthwise of the cage and having its inward movement arrested by engagement with the abutment shoulders of the cage, thereby limiting the relative movement of the shell and cage to less than the full compression stroke of the mechanism; friction shoes within the shell; wedge means cooperating with the shoes, said shoes.

2. In a friction shock absorbing mechanism, the combination with a spring cage castin of a friction shell of regular hexagonal formation, said shell and cage being relatively movable, said cage being open at the forward end and having spaced top'and bottom walls presenting transverse abutment shoulders at the forward ends thereof, spaced vertical side walls extending forwardly beyond said top and bottom walls and having transversely alined, vertically disposed retaining shoulders spaced outwardly of said abutment shoulders, said side walls having guidefseotions extending outwardly of the V 6 i I I 1,877,329

retaining shoulders ander'nbracing' said shell, said outwardly extending sectionshavingfiat interior guide-faces, saidshellj-having *re'la- V tiv-ely wide, longitudinally extending, cen 5 tral guide ribsprojectingifrom oppositesides thereof, said ribs having flat longitudinally disposed outer faces, said ribs being embraced bysaid guide sections of the side walls of the sage and said faces of the ri'los slidablyhens 10 gagingthe'faces of said all sections to guide the shell "for longitudinal 'movement, said shelk having laterally projecting, vertica1- retaining flanges'at the innenend thereof engagedbetween said retaining andst'op'shoulders; friction ineans'cooperating with the .2: she11;and spring means withintheeafge yieldingly, opposing relative movement of the she11'=and cage and *also yi'eldingly opposing relative 1 movement of the shell "and "friction means. U g 36 In witness that "I"laim theiforegoing I have hereunto subscribed my name this 14th day'of April 1930.

s v GEQRGE A. JOHNSCN. 

